Jet interlacers of natural and synthetic fibers are known. In U.S. Pat. No. 2,884,756, for example, there is disclosed an apparatus and process for producing a bulked yarn, wherein a smooth or flat yarn is drawn in from the side (see FIG. 3 therein) into an aspirator-type device. The yarn is withdrawn from the device at a lesser speed, whereby the action of fluid within the aspirator zone causes the individual filaments of the yarn therein to form small loops and the filaments bind among themselves. As noted at column 3, the yarn is withdrawn from the device at an abrupt angle. The device in U.S. Pat. No. 2,997,771 is similar in design and operation, but has an even greater flared exit orifice. See also U.S. Pat. No. 3,103,731.
U.S. Pat. No. 3,026,597 is an example of an interlacing/texturing jet in which the fluid for interlacing/texturing enters from one side of the yarn conduit. In this device, the yarn conduit or passage is tapered uniformly from the inlet end to its exit. The fluid passage communicates with the yarn passage about midway through the device. See also U.S. Pat. No. 3,665,566 for another example of side entry fluid inlets.
U.S. Pat. No. 3,574,249 describes a yarn threadline treating apparatus including a series of guides for the threadline associated with a fluid withdrawal enclosure. U.S. Pat. No. 4,188,692 describes an air jet device having alternate inlets to the yarn passageway and an angled air inlet.
U.S. Pat. Nos. 3,846,968 and 4,223,520 are typical of the use of such devices as air jets to entangle multiple ends of synthetic filaments. U.S. Pat. No. 4,318,210 reflects the use of a hot air device for hot drawing yarn drawn at an angle over pins 12. Finally, U.S. Pat. No. 4,570,312 describes a method and process for air entangling a plurality of yarn ends.
It is a characteristic of these devices, regardless of the materials of construction, to ultimately wear due to continual passage of yarns through the device under varying amounts of frictional forces. In the somewhat random nature of contacting the yarn filaments with the jet surface, wear from device to device is uneven, and much care and exercise must be taken to prevent the inconsistencies in wear from being translated into inconsistencies in the entangled product being made.
This is especially true for jets in which yarn is fed thereto in angled relationship to the yarn passage. The tensions created in dragging the yarn through the jet entrance lowers the entangling performance of the jet.